EDMONTON - The great licence plate fight between Alberta and Saskatchewan may be escalating into a much larger conflict.

Alberta Economic Development Minister Deron Bilous says there will be -- in his words -- "consequences" if Saskatchewan does not roll back its ban on Alberta licence plates on its job sites.

Bilous says Saskatchewan has six days to end the ban or face a lawsuit on the grounds it is violating free trade rules.

In the meantime, Bilous said Alberta will consider other retaliatory measures but declined to be more specific.

Saskatchewan's Infrastructure Minister David Marit says the ban was imposed because Alberta has similar rules for Saskatchewan contractors and Alberta contractors have an unfair advantage because they don't pay a provincial sales tax.

Bilous says Alberta does not have rules mandating Saskatchewan workers have Alberta plates, and he says the Saskatchewan government is not returning his calls to discuss the issue.